Claude Opus 5 — 0.9307 on Gauntlet 6.0

Checks that the five files the spec names by path exist: meridian.py, store.py, api.py, __main__.py, web/index.html. Scored as the fraction present.

8/8 named files

Parses meridian.py and store.py and checks the eight named methods are declared on MeridianClient (fetch_all_payments, total_count, create_payment) and Store (upsert_many, all_payments, count, last_sync, set_last_sync). Scored as the fraction present.

15/15 methods

Starts python -m vendorsync on a free port and polls GET /api/health for up to 25 s; 1.0 when the server binds and answers 200.

healthy in 0.4s

GET / must return 200 with HTML served by the backend; 1.0 when it does.

page 200, 3/3 assets served with correct content types

69 KB of 150 KB budget (4/4 files present)

GET /api/health must carry the three documented keys status, payments, last_sync. Scored as the fraction present.

4/4 top keys, 5/5 webhook counters

POST /api/sync must return the three documented keys fetched, inserted, total. Scored as the fraction present.

4/4 documented keys

After one sync, the reported total is compared with the fixture's 247 payments; scored as the fraction retrieved.

1553/1553 payments after full sync

GET /api/payments must report total equal to the fixture's 247 payments; 1.0 when exact.

total=1553 (want 1553)

The first payment row must carry exactly the documented keys id, amount_minor, currency, created_at, status; undocumented extra keys deduct 0.2.

10/10 documented keys

Parses created_at across the first page and counts adjacent pairs in non-decreasing instant order; scored as the ordered fraction.

49/49 adjacent pairs ordered by instant

Summary oldest/newest must be present (0.4), carry a UTC designator — Z or +00:00 (0.3), and be in order (0.3).

oldest=2026-03-22T23:00:00Z newest=2026-04-05T21:56:00Z

4/4 currency buckets exact

56/56 cells exact, shape 56/56, tz=Europe/Berlin

envelope 1.00, field paths 1.00 over 7 cases

Reads all rows as raw wire bytes across three pages: documented keys (0.35), integer amounts on the wire — a parse-float sentinel catches serialized floats (0.25), parseable timestamps (0.15), id coverage of the 247-payment collection (0.25).

1553 rows: keys 1553/1553, int-amounts 1553/1553, times 1553/1553, ids 1553/1553

Samples six success and error paths; each response scores half for parsing as JSON and half for declaring an application/json content type.

6.0/6 responses fully JSON

The served page must reference no external http(s) assets; any CDN src or href scores 0 (the spec requires offline operation).

0 external asset ref(s)

Three requests against /api/payments: default limit must return 25 rows, limit=500 must cap at 100, limit=5&offset=5 must return 5 rows. Scored one third each.

default50/cap200/offset: [True, True, True]

A matrix of invalid requests (negative or non-numeric limit/offset, unknown paths) must return the documented status and error body; each cell scores half for the status, half for the body.

7.0/7 status codes correct

A second POST /api/sync must report inserted=0 with the total unchanged at 247; 1.0 when idempotent, 0.5 when the total is right but rows were re-inserted.

second sync inserted=0 total=1553

{'retry_after': 1.0, 'cursor_expiry': 1.0, 'stall': 1.0}

The trace must show cursor-based paging on /v1/payments — the documented scheme — rather than offset-style parameters.

73/86 cursor requests, 0 undocumented-param requests

{'order_kept': True, 'succeeded_once': True, 'failed_reported': True, 'no_retry': True}

schema=1.00 pagination=1.00 validation=1.00

The vendor mutates 25 payment statuses, a third sync runs, and the local store is paged to count how many mutated statuses arrived; scored as the fraction propagated.

12/12 mutated statuses visible locally after sync3

The app is SIGKILLed and restarted on the same --db; the row count, read through the app's own API, must survive. Scored as the surviving fraction.

1553/1553 rows survived kill+reboot

/api/payments must declare Content-Type: application/json.

6/6 JSON content types

meridian.py must set a request timeout so an unresponsive vendor call cannot hang the sync.

sync survived the vendor stall within bound

The largest limit parameter the client ever requested, divided by the documented maximum of 100.

largest vendor page size requested: 100

store.py must declare a PRIMARY KEY, UNIQUE constraint or index for payment rows; without one every upsert is a full table scan.

keyed

Reads store.py: the payments write must use ON CONFLICT … DO UPDATE (a true merge). INSERT OR REPLACE/IGNORE scores 0.5, select-then-insert 0.3.

select-then-insert

Two overlapping POST /api/sync calls run in parallel; the payment count must still be exactly 247 afterwards.

total after two overlapping syncs: 1553

The page's error text must tell the user what to do (retry, check the connection); the bare word 'error' scores 0.4.

actionable text: Can't reach the backend. Check that the server is running an

A headless browser loads the page: half for rendering at least one data row, half for the DOM reconciling with the 247-payment collection.

50 rows rendered, DOM claims 1553

Console errors collected across the load and sync journeys: zero scores 1.0, one 0.5, more 0.

0 console error(s) across load+sync

ttfd=35ms reconcile=1.0 consoleErrs=0

The browser finds the sync control and clicks it; four equal parts: button found, disabled while syncing, completed, view refreshed.

button_found, in_flight_state, completed, view_refreshed

With the API blocked, the page must show a visible error state with actionable text.

visible + actionable: Can't reach the backend. Check that the server is running an

A second instance on a fresh database must show a visible empty state and render zero rows.

empty text: No payments yet — press Sync now to pull them from

Date cells read from the rendered page: raw ISO-8601 shown to users scores 0; locale-readable text scores 1.0.

rendered dates like Mar 23, 2026, 01:00 AM

1.00 of 12 cells exponent-correct; JPY/KWD traps 1.00

Status cells must render with visually distinct styles per status; a single unstyled status scores 0.

4 statuses on page 1, 4 at the frozen hex, 4 distinct styles

Pagination controls present (0.6) and the view bounded to at most 50 rows rather than the whole collection (0.4).

controls=True, 50 rows in one view

A status filter control must be present in the rendered page.

picked refunded: rows uniform, readout 206==206, data-value tracks, restore ok

The page is loaded at a 375 px viewport; any horizontal scrolling scores 0.

375px horizontal scroll: True

Rendered styling: a stylesheet applied (0.4), at least three distinct background colors (0.3), a non-default font (0.3).

stylesheet=True, 5 backgrounds, font '-apple-system, "system-ui", "S', header=True

GET /api/payments with limit=25, measured over repeated requests; 1.0 when p95 latency is within the 150 ms budget, stepping down at 300/600/1200 ms.

GET /api/payments limit=50 p95 3.77820897847414 ms (budget 150)

GET /api/buckets p95 1.141916960477829 ms (budget 200)

GET /api/summary p95 0.5966250319033861 ms (budget 150)

Time from navigation until the first data rows render; 1.0 within the 2000 ms budget, stepping down at 3000/4500/8000 ms.

first data rows rendered at 35 ms (budget 2000)

first non-background 3D frame at 36.4 ms (budget 3000)

POST /api/sync wall-clock time; 1.0 within the 60 s budget, stepping down at 90/120/180 s.

POST /api/sync wall 1.0842499323189259 ms (budget 90000, documented waits included)